The present invention relates to streaming media data. More particularly, the present invention relates to methods and apparatus for splitting streams of media data while reducing traffic bursts.
With conventional television or radio broadcasting, powerful transmitters are used to broadcast encoded audio and/or video signals across the airwaves. These signals are received and converted back to audio and/or video signals for output to users. In this type of open air broadcasting, the amount of broadcast power does not vary depending upon the number of viewers or listeners. For example, a radio station may output 5000 Megawatts of power day and night, although the number of listeners at night may be much smaller than during the day.
The same situation is also believed to be true with cable-TV broadcasts. Specifically, for cable TV, signals are transmitted across cable TV lines with the help of a number of cable repeaters. With this type of broadcasting, the amount of broadcast power also does not vary depending upon the number of viewers or listeners. For example, a cable TV station such as CNN outputs the same signal day and night, regardless of the actual viewership.
It has been discovered by the inventors, that in contrast to the above broadcasting models, the situation is different with wide-area-network (WAN) based broadcasts, such as live Internet broadcasts. In particular, attempting to broadcast across the Internet, raises many new problems not considered before. For example, it often matters to an Internet broadcaster how many users are receiving a broadcast at one time. Typical Internet broadcast servers have only a limited amount of output bandwidth, however each user that receives a transmission from the server requires some of that output bandwidth. Accordingly, each server can only support a limited number of users at a time.
It has also been discovered by the inventors that when delivering “live” Internet broadcasts to users, typically via streams of packetized media data, the broadcasting server produces high peaks of network traffic. In the present disclosure, high peaks of network traffic refer to a large number of data packets being delivered in a short amount of time. Traffic peaks are also referred to below as traffic bursts.
One drawback in having high peaks or high bursts of traffic is that downstream routers, servers, and the like may not be able to handle the amounts of traffic. As is known, routers and servers and the like have internal buffers to buffer input traffic in the case where the input traffic rate is faster than the output traffic rate. However, when the traffic burst is very high or large, these buffers fill up and data packets are dropped. As a result, users coupled to the routers or the like receive broadcast data streams that are degraded in quality and in smoothness because of the dropped data packets.
Thus what is required are improved methods and apparatus for providing Internet broadcasts that better address the problems described above, while reducing the drawbacks.